Field of the Disclosure
The present invention relates in general to belled pipes and, in particular, to a system, method and apparatus for forming grooves in the bells of pipes.
Description of the Prior Art
Conventional pipe bell grooving is performed with a machine that essentially uses a custom router head that follows the inside surface of the bell of the pipe. While the entire pipe is rotated, one or more grooves are cut into the internal surface of the bell. However, because the axis of the router is strictly fixed in relation to the axis of the pipe barrel (the barrel being the portion of the pipe that is not belled), any misalignment of the bell centerline axis with the barrel centerline axis can cause “walking” grooves (i.e., grooves that are not properly formed) within the bell. This can result in product that does not function properly and must be scrapped.
Angular misalignment is likely to cause the most problems in this regard. Even with a miniscule 0.25 degree angular misalignment between the pipe and the machine, the groove position within the bell will “walk” a total of more than 0.075 inches. The clearance between the groove and the spline that goes in the groove (at the time of pipe installation) is generally 0.125 inches, almost all of which is required for a standard tolerance stack. Thus, any deviations over about 0.015 inches of groove “walk” will result in scrapped parts. Accordingly, improvements in pipe bell grooving continue to be of interest.
The use of the same reference symbols in different drawings indicates similar or identical items.